Update on type 2 immunity.

This review article summarizes and comments on the mechanistic work on type 2 immunity published between January 2022 and September 2024. Type 2 immunity is characterized by the production of IL-4, IL-5, IL-9, and IL-13 and is primarily known for its detrimental roles in allergic diseases and its protective roles in helminth infections. Other functions of type 2 immunity include protection against venoms and toxins, wound healing, tissue remodeling, regeneration, and metabolic homeostasis. This review article discusses novel findings on regulation of these processes and disease states by select cells and humoral factors of type 2 immunity, including group 2 innate lymphoid cells, CD4 T cells, mast cells, peripheral neurons, and IgE. The article also describes novel discoveries on regulation of these factors and cells by environmental exposures and the host. Further, the article discusses select genetic mouse models that were developed recently and have the potential to accelerate the field. Finally, the article comments on the significance of novel discoveries to clinical medicine, including drug development.